//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <string>

// iterator erase(const_iterator first, const_iterator last);

#include <string>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

template <class S>
TEST_CONSTEXPR_CXX20 void
test(S s, typename S::difference_type pos, typename S::difference_type n, S expected)
{
    typename S::const_iterator first = s.cbegin() + pos;
    typename S::const_iterator last = s.cbegin() + pos + n;
    typename S::iterator i = s.erase(first, last);
    LIBCPP_ASSERT(s.__invariants());
    assert(s[s.size()] == typename S::value_type());
    assert(s == expected);
    assert(i - s.begin() == pos);
}

bool test() {
  {
    typedef std::string S;
    test(S(""), 0, 0, S(""));
    test(S("abcde"), 0, 0, S("abcde"));
    test(S("abcde"), 0, 1, S("bcde"));
    test(S("abcde"), 0, 2, S("cde"));
    test(S("abcde"), 0, 4, S("e"));
    test(S("abcde"), 0, 5, S(""));
    test(S("abcde"), 1, 0, S("abcde"));
    test(S("abcde"), 1, 1, S("acde"));
    test(S("abcde"), 1, 2, S("ade"));
    test(S("abcde"), 1, 3, S("ae"));
    test(S("abcde"), 1, 4, S("a"));
    test(S("abcde"), 2, 0, S("abcde"));
    test(S("abcde"), 2, 1, S("abde"));
    test(S("abcde"), 2, 2, S("abe"));
    test(S("abcde"), 2, 3, S("ab"));
    test(S("abcde"), 4, 0, S("abcde"));
    test(S("abcde"), 4, 1, S("abcd"));
    test(S("abcde"), 5, 0, S("abcde"));
    test(S("abcdefghij"), 0, 0, S("abcdefghij"));
    test(S("abcdefghij"), 0, 1, S("bcdefghij"));
    test(S("abcdefghij"), 0, 5, S("fghij"));
    test(S("abcdefghij"), 0, 9, S("j"));
    test(S("abcdefghij"), 0, 10, S(""));
    test(S("abcdefghij"), 1, 0, S("abcdefghij"));
    test(S("abcdefghij"), 1, 1, S("acdefghij"));
    test(S("abcdefghij"), 1, 4, S("afghij"));
    test(S("abcdefghij"), 1, 8, S("aj"));
    test(S("abcdefghij"), 1, 9, S("a"));
    test(S("abcdefghij"), 5, 0, S("abcdefghij"));
    test(S("abcdefghij"), 5, 1, S("abcdeghij"));
    test(S("abcdefghij"), 5, 2, S("abcdehij"));
    test(S("abcdefghij"), 5, 4, S("abcdej"));
    test(S("abcdefghij"), 5, 5, S("abcde"));
    test(S("abcdefghij"), 9, 0, S("abcdefghij"));
    test(S("abcdefghij"), 9, 1, S("abcdefghi"));
    test(S("abcdefghij"), 10, 0, S("abcdefghij"));
    test(S("abcdefghijklmnopqrst"), 0, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 0, 1, S("bcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 0, 10, S("klmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 0, 19, S("t"));
    test(S("abcdefghijklmnopqrst"), 0, 20, S(""));
    test(S("abcdefghijklmnopqrst"), 1, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 1, 1, S("acdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 1, 9, S("aklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 1, 18, S("at"));
    test(S("abcdefghijklmnopqrst"), 1, 19, S("a"));
    test(S("abcdefghijklmnopqrst"), 10, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 10, 1, S("abcdefghijlmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 10, 5, S("abcdefghijpqrst"));
    test(S("abcdefghijklmnopqrst"), 10, 9, S("abcdefghijt"));
    test(S("abcdefghijklmnopqrst"), 10, 10, S("abcdefghij"));
    test(S("abcdefghijklmnopqrst"), 19, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 19, 1, S("abcdefghijklmnopqrs"));
    test(S("abcdefghijklmnopqrst"), 20, 0, S("abcdefghijklmnopqrst"));
  }
#if TEST_STD_VER >= 11
  {
    typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
    test(S(""), 0, 0, S(""));
    test(S("abcde"), 0, 0, S("abcde"));
    test(S("abcde"), 0, 1, S("bcde"));
    test(S("abcde"), 0, 2, S("cde"));
    test(S("abcde"), 0, 4, S("e"));
    test(S("abcde"), 0, 5, S(""));
    test(S("abcde"), 1, 0, S("abcde"));
    test(S("abcde"), 1, 1, S("acde"));
    test(S("abcde"), 1, 2, S("ade"));
    test(S("abcde"), 1, 3, S("ae"));
    test(S("abcde"), 1, 4, S("a"));
    test(S("abcde"), 2, 0, S("abcde"));
    test(S("abcde"), 2, 1, S("abde"));
    test(S("abcde"), 2, 2, S("abe"));
    test(S("abcde"), 2, 3, S("ab"));
    test(S("abcde"), 4, 0, S("abcde"));
    test(S("abcde"), 4, 1, S("abcd"));
    test(S("abcde"), 5, 0, S("abcde"));
    test(S("abcdefghij"), 0, 0, S("abcdefghij"));
    test(S("abcdefghij"), 0, 1, S("bcdefghij"));
    test(S("abcdefghij"), 0, 5, S("fghij"));
    test(S("abcdefghij"), 0, 9, S("j"));
    test(S("abcdefghij"), 0, 10, S(""));
    test(S("abcdefghij"), 1, 0, S("abcdefghij"));
    test(S("abcdefghij"), 1, 1, S("acdefghij"));
    test(S("abcdefghij"), 1, 4, S("afghij"));
    test(S("abcdefghij"), 1, 8, S("aj"));
    test(S("abcdefghij"), 1, 9, S("a"));
    test(S("abcdefghij"), 5, 0, S("abcdefghij"));
    test(S("abcdefghij"), 5, 1, S("abcdeghij"));
    test(S("abcdefghij"), 5, 2, S("abcdehij"));
    test(S("abcdefghij"), 5, 4, S("abcdej"));
    test(S("abcdefghij"), 5, 5, S("abcde"));
    test(S("abcdefghij"), 9, 0, S("abcdefghij"));
    test(S("abcdefghij"), 9, 1, S("abcdefghi"));
    test(S("abcdefghij"), 10, 0, S("abcdefghij"));
    test(S("abcdefghijklmnopqrst"), 0, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 0, 1, S("bcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 0, 10, S("klmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 0, 19, S("t"));
    test(S("abcdefghijklmnopqrst"), 0, 20, S(""));
    test(S("abcdefghijklmnopqrst"), 1, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 1, 1, S("acdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 1, 9, S("aklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 1, 18, S("at"));
    test(S("abcdefghijklmnopqrst"), 1, 19, S("a"));
    test(S("abcdefghijklmnopqrst"), 10, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 10, 1, S("abcdefghijlmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 10, 5, S("abcdefghijpqrst"));
    test(S("abcdefghijklmnopqrst"), 10, 9, S("abcdefghijt"));
    test(S("abcdefghijklmnopqrst"), 10, 10, S("abcdefghij"));
    test(S("abcdefghijklmnopqrst"), 19, 0, S("abcdefghijklmnopqrst"));
    test(S("abcdefghijklmnopqrst"), 19, 1, S("abcdefghijklmnopqrs"));
    test(S("abcdefghijklmnopqrst"), 20, 0, S("abcdefghijklmnopqrst"));
  }
#endif

  return true;
}

int main(int, char**)
{
  test();
#if TEST_STD_VER > 17
  // static_assert(test());
#endif

  return 0;
}
